Body-area sensor network featuring micropyramids for sports healthcare

Monitoring physiological signals of the human body can provide extremely important information for sports healthcare,preventing injuries and providing efficient guidance for individual sports.However,the signals related to human healthcare involve both subtle and vigorous signals,making it difficult for a sensor to satisfy the full-scale monitoring at the same time.Here,a novel conductive elastomer featuring homogeneously micropyramid-structured PDMS/CNT composite is used to fabricate highperformance piezoresistive sensors by a drop-casting method.Benefiting from the significant increase in the contact area of microstructure during deformation,the flexible sensor presents a broad detection range(up to 185.5 kPa),fast response/recovery time(44/13 ms),ultrahigh sensitivity(242.4 kPa–1)and excellent durability over 8,000 cycles.As a proof of concept,the as-fabricated pressure sensor can be used for body-area sports healthcare,and enable the detection of full-scale pressure distribution.Considering the fabulous sensing performance,the sensor may potentially become promising in personal sports healthcare and telemedicine monitoring.

From high-yield Ti3AlCN ceramics to high-quality Ti3CNTx MXenes through eliminating Al segregation

Ti3CNTx MXenes with unique electrical conductivity can be widely applied for supercapacitors and electromagnetic shielding.However,its relatively low-yield quaternary nitrogen-containing Ti3AlCN ce ramics precursor(less than 50%),due to the inevitable Al segregation during the synthesizing process,significantly hindered its widely commercial applications.Herein,we employed the controllable AlNoversaturation precursor strategy to precisely tune the phase transition point of quaternary Ti3AlCN ceramics to obtain high-yield Ti3 AlCN precursor for the purpose of high conductivity Ti3 CNTx MXenes.Combined energy dispersive X-ray spectrometer(XRD)with X-ray photoelectron spectroscopy(XPS)characterizations,the yield of the quaternary nitrogen-containing Ti3 AlCN ceramics was evidently proved to be up to 70%,which is 1.4 times than that of previously reported works.Such relatively highyield quaternary Ti3AlCN is mainly ascribed to the elimination of Al segregation.Based on it,we further developed accordion-like two-dimensional(2D)MXene via hydrofluoric acid etch and vacuum freezedry.This novel accordion-like 2D Ti3CNTx MXene possesses high electrochemical capacitive properties(209 F/g).Therefore,this controllable AlN-oversaturation precursor strategy will pave a way to exploit costly high-yield MAX ceramics precursor for high conductivity MXenes and also play a powerful role in promoting their practical applications including electrical and magnetic engineering fields.

Understanding the Percolation Effect in Triboelectric Nanogenerator with Conductive Intermediate Layer

Introducing the conductive intermediate layer into a triboelectric nanogenerator(TENG)has been proved as an efficient way to enhance the surface charge density that is attributed to the enhancement of the dielectric permittivity.However,far too little attention has been paid to the companion percolation,another key element to affect the output.Here,the TENG with MXeneembedded polyvinylidene fluoride(PVDF)composite film is fabricated,and the dependence of the output capability on the MXene loading is investigated experimentally and theoretically.Specifically,the surface charge density mainly depends on the dielectric permittivity at lower MXene loadings,and in contrast,the percolation becomes the degrading factor with the further increase of the conductive loadings.At the balance between the dielectric and percolation properties,the surface charge density of the MXene-modified TENG obtained 350%enhancement compared to that with the pure PVDF.This work shed new light on understanding the dielectric and percolation effect in TENG,which renders a universal strategy for the high-performance triboelectronics.